LMS-931 Add Save button to Amendment Preview

Feature improvement summary

Add Save button to Amendment Preview. Consider whether ‘Save and Close’ should become two separate buttons.

Original Description

It would be useful to have a “save” button alongside the “save and close” button or having to click “next” or “previous” to save a comment in Amendment Preview mode, especially if wanting to save where you’re up to with a comment (rather than having to navigate away from that comment).